I am having the exact same issue. I am currently seeking a workaround.

I learned that the 130 and 140 for GLSL are shader language versions. Mac OS does not generally support OpenGL up to that point but maybe some versions will be compatible. So the problem I that, without a working shader (the shaders that come with Ursina all being in versions 130-150), all textures default to black.

From a fellow newbie perspective I think the best way around the problem could be to load a custom shader in version 120, and make sure that the gl-version is compatible with it, applying that shader. I haven't actually managed that yet.